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<a name="boost.proto.as_child"></a><div class="titlepage"></div>
<div class="refnamediv">
<h2><span class="refentrytitle">Function as_child</span></h2>
<p>boost::proto::as_child — A function that wraps non-Proto objects in Proto terminals (by reference) and leaves
          Proto expression types alone.</p>
</div>
<h2 class="refsynopsisdiv-title">Synopsis</h2>
<div class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="../../proto/reference.html#header.boost.proto.traits_hpp" title="Header &lt;boost/proto/traits.hpp&gt;">boost/proto/traits.hpp</a>&gt;

</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> T<span class="special">&gt;</span> 
  <span class="keyword">typename</span> <a class="link" href="result_of/as_child.html" title="Struct template as_child">proto::result_of::as_child</a><span class="special">&lt;</span> <span class="identifier">T</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">type</span> <span class="identifier">as_child</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&amp;</span> t<span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> T<span class="special">&gt;</span> 
  <span class="keyword">typename</span> <a class="link" href="result_of/as_child.html" title="Struct template as_child">proto::result_of::as_child</a><span class="special">&lt;</span> <span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">type</span> <span class="identifier">as_child</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&amp;</span> t<span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <a class="link" href="../../Domain.html" title="Concept Domain">Domain</a><span class="special">,</span> <span class="keyword">typename</span> T<span class="special">&gt;</span> 
  <span class="keyword">typename</span> <a class="link" href="result_of/as_child.html" title="Struct template as_child">proto::result_of::as_child</a><span class="special">&lt;</span> <span class="identifier">T</span><span class="special">,</span> <span class="identifier">Domain</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">type</span> <span class="identifier">as_child</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&amp;</span> t<span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <a class="link" href="../../Domain.html" title="Concept Domain">Domain</a><span class="special">,</span> <span class="keyword">typename</span> T<span class="special">&gt;</span> 
  <span class="keyword">typename</span> <a class="link" href="result_of/as_child.html" title="Struct template as_child">proto::result_of::as_child</a><span class="special">&lt;</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">,</span> <span class="identifier">Domain</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">type</span> 
  <span class="identifier">as_child</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&amp;</span> t<span class="special">)</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="id-1.3.32.5.41.74.4"></a><h2>Description</h2>
<p>
            The <code class="computeroutput">proto::as_child()</code> function returns Proto expression
            objects that are suitable for storage as child nodes in an expression tree. It turns
            non-Proto objects into Proto terminals. Its behavior is domain-specific. By default,
            non-Proto types are held wrapped by reference in a new Proto terminal expression, and
            objects that are already Proto expressions are simply returned by reference.
          </p>
<p>
            If <code class="computeroutput">Domain</code> is not explicitly specified, it is assumed to
            be <code class="computeroutput"><code class="computeroutput"><a class="link" href="default_domain.html" title="Struct default_domain">proto::default_domain</a></code></code>.
          </p>
<p>
            See <code class="computeroutput"><code class="computeroutput"><a class="link" href="domain/as_child.html" title="Struct template as_child">proto::domain::as_child</a></code>&lt;&gt;</code>
            for a complete description of this function's default behavior.
          </p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term">Returns:</span></p></td>
<td><code class="computeroutput">typename Domain::template as_child&lt; T &gt;()(t)</code></td>
</tr></tbody>
</table></div>
</div>
</div>
<div class="copyright-footer">Copyright © 2008 Eric Niebler<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
      </p>
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